In recent years, with enhanced accuracy and advanced functionality for vehicle control by an electronic control unit (ECU), many sensors and actuators are provided for the acquisition of various vehicle information (including vehicle surrounding information) and control over vehicular sections, and the number of communication lines between these sensors and actuators and the ECU has considerably increased in an automobile. Against this backdrop, Patent Document 1 discloses the application of a power line communication device using a power line for a direct-current power supply as a communication line for communicating vehicle information sensor data and control data. According to Patent Document 1, a communication phase and a power feeding phase are provided for the use of the power line and the power line is used for either communication or power feeding per phase.